Is “Knucklehead” a Scrabble word?
Yes
KNUCKLEHEAD
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Knucklehead
/ˈnʌkl̩ˌhɛd/
noun
1.An idiot; a stupid or inept person
“Don't stick that screwdriver into the live electrical outlet, you knucklehead!”
2.An endearing remark directed to siblings or one's own children; a child who is acting silly.
“Come over here you knucklehead(s)! I'm going to tickle you!”